1. Technical Field
The present invention relates to an internal combustion engine system including an internal combustion engine with a purification catalyst provided in an exhaust line thereof, a fuel injection module configured to inject a fuel into the internal combustion engine, an exhaust recirculation module arranged to recirculate part of exhaust of the internal combustion engine into a gas intake line of the internal combustion engine, and a temperature-reflecting physical quantity detector constructed to measure a temperature-reflecting physical quantity representing temperature of the internal combustion engine, and a control method of the internal combustion engine system.
2. Related Art
One proposed structure of an internal combustion engine system is equipped with an EGR (exhaust gas recirculation) device designed to recirculate the exhaust gas into a gas intake line (see, for example, Patent Document 1). The EGR device mounted on the internal combustion engine system sets an EGR rate according to the engine water temperature and controls on and off an EGR valve to recirculate the exhaust gas into the gas intake line at the set EGR rate. Such controlled recirculation of the exhaust gas aims to lower the temperature of the exhaust gas and thereby prevent an excessive increase of the engine temperature.
Patent Document 1: Japanese Patent Laid-Open No. H07-317606